Chaplygin, Daniil

Titenkova K., Chaplygin D.A., Fershtat L.L.

AbstractElectrochemistry became a unique and powerful tool for the preparation of a plethora of valuable chemical species including functional materials, drug candidates and clinically approved pharmaceuticals. Organic electrosynthesis well satisfies main goals of green chemistry development and is considered as one of the useful approaches toward the creation of sustainable future. Since nitrogen heterocyclic scaffolds still retain their importance for the construction of novel materials and medications, one of the emerging trends in organic electrochemistry is the discovery of novel green and sustainable synthetic methods toward the assembly of heterocyclic subunits. In this regard, organic electrochemistry provides an efficient platform for environmentally benign generation of various nitrogen‐centered radicals which are prominent intermediates in the synthesis of nitrogen heterocycles. In this Review, recent developments in the creation of green synthetic methods for the construction of nitrogen heterocycles via electrochemical generation of nitrogen‐centered radicals are summarized. The special emphasis is devoted to the influence of solvent, electrodes and electrolytes on the electrochemical step, since these crucial parameters regulate the process efficiency.

Chaplygin D.A., Larin A.A., Meerov D.B., Monogarov K.A., Pronkin D.K., Pivkina A.N., Fershtat L.L.

AbstractA regioselective approach toward the synthesis of a set of new (2‐vinyltetrazolyl)furoxans as potential energetic monomers has been realized. All target energetic materials were thoroughly characterized by spectral and analytical methods. Moreover, crystal structures of two representative heterocyclic systems were studied by single‐crystal X‐ray diffraction. Prepared high‐energy substances have high combined nitrogen‐oxygen content (63‐71 %), high enthalpies of formation and good detonation parameters (D: 6.7–7.8 km s−1; P: 18–28 GPa). Mechanical sensitivities of the synthesized vinyltetrazoles range these explosives from highly sensitive to completely insensitive. Using calculations of molecular electrostatic potentials (ESP), structural factors influencing the impact sensitivity were revealed. Overall, newly synthesized (2‐vinyltetrazolyl)furoxans are of interest as promising energetic monomers due to the presence of the vinyl moiety and explosophoric heterocyclic combination, while their performance exceeds that of benchmark explosive TNT.

Chaplygin D.A., Larin A.A., Fershtat L.L.

An efficient synthesis of N- and S-substituted arylglyoximes via one-pot transformations of available monoarylfuroxans was developed. The proposed approach includes furoxan ring cleavage followed by the generation of α-oximinoacetonitrile oxides which further add N- and S-nucleophiles.

Muravyev N.V., Melnikov I.N., Chaplygin D.A., Fershtat L.L., Monogarov K.A.

Analysis of thermal behavior of liquids is often accompanied by vaporization. In an extreme case, the calorimetric (DSC) experiment reveals the only endothermic evaporation instead of the more valuable thermal decomposition. 3-Methylfuroxan (MMF) is an energetic monosubstituted 1,2,5-oxadiazole N-oxide that shows the above behavior. We investigate the sample mass and confinement effects and show that the pressure DSC allows observing thermal decomposition of target compound at 2.0 MPa. Advanced model-fitting kinetic analysis reveals two global stages, the first of which is a competition between the noncatalytic reaction and autocatalytic one, whereas the second global stage is a second-order reaction. Analysis of MMF thermolysis in solution in dibutyl phthalate shows the activation energy for noncatalytic reaction to be 145.4 ± 1.7 kJ mol−1. To resolve the gas decomposition products in experiments at 0.1 MPa pressure, where the evaporation is abundant, a gas chromatography–mass spectrometry coupled with thermal analyzer was used. Among the gases that are consistent with a furoxan ring rupture by CC and NO bonds (HNCO, CH3CN), we detect CH3COCN that retains CC bond. The formation of geminal cyanonitro compound in the course of thermolysis is proposed to explain the composition of the gas reaction products. Overall, with the range of thermal analysis tools (DSC, PDSC, GC–MS/TGA, thermokinetic modeling) we performed a detailed analysis of thermal transformations of unexplored simple monosubstituted furoxan. The applied methodological approaches could be transferred to other molecular liquids.

Chaplygin D.A., Gorbunov Y.K., Fershtat L.L.

AbstractA regioselective method for an assembly of pharmacologically relevant fully substituted furoxans and isoxazoles using the ring distortion diversity‐oriented approach through the one‐pot ring cleavage/nucleophilic addition/oxidation cascade of monosubstituted furoxans was developed. The described synthetic strategy is highly regioselective and provides single furoxan regioisomers upon utilization of N‐ or S‐nucleophiles. Utilization of the cyanide‐anion as a nucleophile in the same reaction cascade afforded a series of rather rare fully substituted isoxazoles incorporating vicinal nitro and amino functionalities. In addition, synthesized disubstituted furoxans revealed an ability to release NO indicating their strong potential as pharmacologically oriented drug candidates for various biomedical applications.

Chaplygin D.A., Larin A.A., Muravyev N.V., Meerov D.B., Kosareva E.K., Kiselev V.G., Pivkina A.N., Ananyev I.V., Fershtat L.L.

Promising high-nitrogen and eco-friendly energetic salts with excellent detonation performance based on a 5-(trinitromethyl)tetrazolate core were prepared.

Fershtat L.L., Chaplygin D.A., Ananyev I.V., Makhova N.N.

A novel method for the synthesis of a diverse series of functionally substituted five-membered heterocyclic compounds via atom-economic, regio-, and diastereoselective one-pot reaction cascade was developed. This approach involves a ring opening in 4-arylfuroxans to α-oximinoarylacetonitrile oxides followed by [3+2] cycloaddition to various dipolarophiles to afford multisubstituted isoxazoles and isoxazolines. Subsequent azole–azole rearrangement of (oximino)isoxazolines/-isoxazoles, which can be conducted in a one-pot manner, results into functionally substituted furazans formation. The developed protocol is operationally simple, proceeds in mild conditions and with high yields of target heterocyclic systems. Overall, this study represents a new mode of isoxazole and 1,2,5-oxadiazole functionalization strategy, which is useful in medicinal and materials chemistry.

Xie Y., Zhang Z., Wang Y.

AbstractOrganic electrochemical synthesis stands out for its environmentally friendly and efficient characteristics. Among these approaches, halogen‐mediated indirect electrosynthesis has gained significant attention as an efficient strategy for C−N bond formation, widely applied in the synthesis of nitrogen‐containing compounds. This review highlights recent advances in direct C−N bond formation processes for various amines under halogen‐mediated electrosynthetic conditions. The features, scope, limitations, and proposed mechanisms of these transformations are discussed in detail. We aim to provide insights into expanding the applicability of halogen‐mediated electrosynthesis, contributing to the development of sustainable synthetic methodologies.

Mallappa, Chahar M., Choudhary N., Yadav K.K., Qasim M.T., Zairov R., Patel A., Yadav V.K., Jangir M.

Nitrogen-containing heterocyclic compounds (NCHCs) have an important role in the field of medicinal chemistry due to their extensive biological activities and their prevalence in natural compounds, pharmaceuticals, and materials science. Here, we have reviewed the recent advancements in the formulation of NCHCs via multicomponent reactions (MCRs). These reactions, which allow the efficient and eco-friendly formulation of complex molecules, have revolutionized the synthesis of heterocycles such as triazoles, imidazoles, pyrazoles, pyrimidines, and pyridazines. This review has further emphasized the key MCR strategies, including the Biginelli, Ugi, Hantzsch, and Passerini reactions, highlighting their mechanisms, scope, and applications in drug discovery. Finally, we have emphasized the biological evaluation of synthesized NCHCs possessing several pharmacological features like antiallergic, anti-inflammatory, anticancer, antimicrobial, neurological, and analgesic activities. The synthesis of specific NCHC scaffolds and their structure–activity relationships are also explored, emphasizing the significance of these compounds in the development of novel therapeutics.

Huang B.

Budnikov A.S., Leonov N.E., Klenov M.S., Shevchenko M.I., Dvinyaninova T.Y., Krylov I.B., Churakov A.M., Fedyanin I.V., Tartakovsky V.A., Terent’ev A.O.

In this study, the electrochemical coupling of nitrosoarenes with ammonium dinitramide is discovered, leading to the facile construction of the nitro-NNO-azoxy group, which represents an important motif in the design of energetic materials. Compared to known approaches to nitro-NNO-azoxy compounds involving two chemical steps (formation of azoxy group containing a leaving group and its nitration) and demanding expensive, corrosive, and hygroscopic nitronium salts, the presented electrochemical method consists of a single step and is based solely on nitrosoarenes and ammonium dinitramide. The dinitramide salt plays the roles of both the electrolyte and reactant for the coupling. Despite the fact that many side reactions can be expected due to the redox-activity of both the reagents and target products, under optimized conditions the synthesis is performed in an undivided cell under constant current conditions with high current density and can be easily scaled up without a reduction in the product yield. Moreover, the synthesized nitro-NNO-azoxy compounds are discovered to be potent fungicides active against a broad range of phytopathogenic fungi.

Kiselev V.G., Sadykov A.R., Melnikov I.N., Fomenkov I.V., Fershtat L.L., Pivkina A.N., Muravyev N.V.

Thermal stability of 4,4′-dinitro-3,3′-diazenofuroxan, an ultrahigh-performance energetic material, was studied using a complementary combination of thermal analysis and quantum chemical calculations. The Library of Congress is credited for the image of the Sumari, image ID cph 3g08655.

Huang B.

This review critically summarizes the methodological advancements in both photo- and electro-chemical pyrrole synthesis, and categorizes them based on the utilized N-containing precursors.

Shuvaev A., Feoktistov M., Teslenko F., Fershtat L.

AbstractSynthetic electrochemistry may establish direct routes to a preparation of a plethora of organic substances, which are hardly accessible by conventional experimental techniques. Herein, we present an electrochemically‐driven method for an assembly of a broad range of rare heterocyclic mesoionic entities –1,2,3‐triazole 1‐imines. These nitrogen heterocycles were prepared through a transition‐metal‐ and exogenous oxidant‐free strategy using a C/Ni electrode pair. Over 30 examples of thus synthesized 1,2,3‐triazole 1‐imines illustrate selectivity and practical utility of this approach. Key solvent‐controlled reactivity patterns for the formation of the triazole imine scaffold were revealed indicating a modulation ability of the developed approach. These experimental findings were additionally justified based on cyclic voltammetry (CV) data and density functional theory (DFT) calculations. Moreover, according to differential scanning calorimetry (DSC) data, some of the prepared 1,2,3‐triazole 1‐imines correspond to the thermally stable species with an onset decomposition temperature up to 190 °C.

Khoranyan T.E., Larin A.A., Suponitsky K.Y., Ananyev I.V., Melnikov I.N., Kosareva E.K., Muravyev N.V., Dalinger I.L., Pivkina A.N., Fershtat L.L.

Sidunets Y.A., Melekhina V.G., Fershtat L.L.

A straightforward protocol for the synthesis of a previously unknown [1,2,5]oxadiazolo[3,4-d][1,2,3]triazin-7(6H)-one heterocyclic system was developed. The described approach is based on tandem diazotization/azo coupling reactions of (1,2,5-oxadiazolyl)carboxamide derivatives bearing both aromatic and aliphatic substituents. The NO-donor ability of the synthesized furoxano[3,4-d][1,2,3]triazin-7(6H)-ones was additionally evaluated. The elaborated method provides access to novel nitrogen heterocyclic compounds with potential applications as drug candidates or thermostable components of functional organic materials.

Egorov M.P., Ananikov V.P., Baskir E.G., Boganov S.E., Bogdan V.I., Vereshchagin A.N., Vil’ V.A., Dalinger I.L., Dilman A.D., Eliseev O.L., Zlotin S.G., Knyazeva E.A., Kogan V.M., Kononov L.O., Krayushkin M.M., et. al.

A key goal of organic chemistry is to develop new principles for the control of reactions, which can be used to create promising materials demanded in all fields of scientific research and industry. This review is an overview of the scientific advances, which have been made by the N. D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences in the past decade within the framework of current trends in organic chemistry. The review covers the results, which are significant for fundamental research and hold great promise for the application in different areas, from the production of materials, petrochemistry, and chemical ecology to medicine, agriculture, and food industry.

Charushin Valery N., Verbitskiy Egor V., Chupakhin Oleg N., Vorobyeva Daria V., Gribanov Pavel S., Osipov Sergey N., Ivanov Andrey V., Martynovskaya Svetlana V., Sagitova Elena F., Dyachenko Vladimir D., Dyachenko Ivan V., Krivokolysko Sergey G., Dotsenko Viktor V., Aksenov Aleksandr V., Aksenov Dmitrii A., et. al.

The chemistry of heterocyclic compounds has traditionally been and remains a bright area of chemical science in Russia. This is due to the fact that many heterocycles find the widest application. These compounds are the key structural fragments of most drugs, plant protection agents. Many natural compounds are also derivatives of heterocycles. At present, more than half of the hundreds of millions of known chemical compounds are heterocycles. This collective review is devoted to the achievements of Russian chemists in this field over the last 15–20 years. The review presents the achievements of leading heterocyclists representing both RAS institutes and university science. It is worth noting the wide scope of the review, both in terms of the geography of author teams, covering the whole of our large country, and in terms of the diversity of research areas. Practically all major types of heterocycles are represented in the review. The special attention is focused on the practical applications of heterocycles in the design of new drugs and biologically active compounds, high-energy molecules, materials for organic electronics and photovoltaics, new ligands for coordination chemistry, and many other rapidly developing areas. These practical advances would not be possible without the development of new fundamental transformations in heterocyclic chemistry.The bibliography includes 2237 references.

Zhang H., Zou Y., Hao X., Liu Y., Zhang G., Dong Z., Ye Z.

Bhatia P., Ghule V.D., Kumar D.

Various types of materials have been explored in the pursuit of high energy density materials (HEDMs) that have balanced energy and stability. Among them, energetic salts show numerous advantages, such as lower vapor pressures, high physical stabilities, and the opportunity for favourable tuning by careful selection of cations/anions. Nitrogen-rich bases are generally used as cations for energetic salt formation. While the synthesis of salts with larger cations lowers the sensitivity, smaller cations aid better energetic performance. A combination of both in the same ionic moieties might help in the formation of a superior explosive. In this work, a facile route for the synthesis of mixed dicationic energetic salts based on 1-((1H-tetrazol-5-yl)methyl)-3,5-dinitro-1H-pyrazol-4-ol (compound 1) has been explored by various combinations of bigger and smaller cations (compounds 4-10). All the synthesized energetic salts showed high positive heats of formation, energetic performance comparable to TATB, excellent stability towards impact and friction, and acceptable thermal stabilities. This improved technique will provide an additional option for fine-tuning the energetic properties of HEDMs and will facilitate in exploring the role of various cations in the overall performance of the energetic compounds.

Shaferov Alexander V., Fershtat Leonid L.

The study of high-energy materials based on poly nitrogen- and nitrogen-oxygen-containing heterocycles is one of the most important and relevant modern interdisciplinary research areas at the intersection of organic and physical chemistry and materials science. Among such heterocycles, 1,2,4-oxadiazole ring is a rather interesting building block for the synthesis of new energetic compounds. Although the chemistry of 1,2,4-oxadiazoles has been developed for more than 100 years, high-energy materials based on these heterocycles have only recently become known and are currently one of the "hot spots" in this field of science. This review systematizes recently published methods for the synthesis and features of the reactivity of 1,2,4-oxadiazole-based energetic compounds. Mono- and bis(1,2,4-oxadiazoles) as well as structures containing other azoles such as pyrazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-triazole, 1,2,4-triazole and tetrazole are considered. For the series of structurally similar compounds, their physicochemical properties are summarized and the factors affecting a particular parameter are discussed.Bibliography — 123 references.

Tamuliene J., Sarlauskas J.

The current work is dedicated to the search for new high-energy materials (HEMs) with improved characteristics, which are gained through agglomeration with salts. The research was performed by Becke’s three-parameter hybrid functional approach, with non-local correlation provided by Lee, Yang, and Parr, and the cc-pVTZ basis set. The structure, total energy, and heat of formation, presented as binding energy per atom of the most stable compounds formed due to 3-amino-5-[(2, 4, 6-trinitrophenyl) amino]-1H-1,2,4-triazole (APATO) within selected salts, were obtained to foresee its influence on resistance to shock stimuli, detonation pressure, and velocity of the materials under study. The results obtained allow us to foresee that only agglomeration with precise salts could lead to a significant improvement in the stability of the specific high-energy materials and resistance to shock stimuli. We also show that agglomeration leads to better energetic properties of the above-mentioned compound, although the improvement may be insignificant in some cases.

Titenkova K.Y., Shuvaev A.D., Teslenko F.E., Zhilin E.S., Fershtat L.L.

A green electrochemical approach for the intramolecular formation of N–N bonds was realized to prepare a diverse range of valuable 1,2,3-triazole 1-oxides, making this nitrogen heterocycle subclass a full member of classes of organic compounds.

Kofen M., Klapötke T.M., Stierstorfer J.

The search for balance between the high enthalpy of formation and thermal stability of 1-(Azidomethyl)-5 H -tetrazole (AzMT) with the good oxygen balance and density of 1-(Nitratomethyl)-5 H -tetrazole (1-NaMT) led to the first synthesis of 1-(Nitromethyl)-5 H -tetrazole (1-NMT). As a representative of the rare class of N -nitromethyl azoles, it exhibits an astonishingly, but surprisingly, high stability towards mechanical stimuli. Next to a complete characterization of 1-NMT, this work includes a comprehensive investigation of Energetic Coordination Compounds (ECCs) of 1-NMT with several 3d metal nitrates, chlorates, and perchlorates. • N-Nitromethyl azoles are extremely rare, 1-NMT is the fourth ever reported. • Nitromethyl groups yield to better oxygen contents and lower sensitivities. • Sustainable chemistry: Nitration optimization and recovery of the starting material. • Energetic Coordination Compounds increase the thermal stabilities. • ECCs show rapid DDT and laser ignitability. The hardly accessible N -nitromethyl moiety is introduced onto the 1,5-tetrazole scaffold, representing the fourth and fifth ever synthesized N -nitromethyl azoles. Both compounds 1-(Nitromethyl)-5 H -tetrazole ( 2a ) and 2-(Nitromethyl)-5 H -tetrazole ( 2b ) are thoroughly analyzed by low-temperature single-crystal X-ray diffraction experiments, complemented by elemental analysis, multinuclear ( 1 H, 13 C, 14 N, 15 N) NMR as well as IR spectroscopy. Sensitivity measurements towards external stimuli revealed two highly insensitive compounds. Additionally, 2a was applied as ligand for energetic coordination compounds of 3d transition metals (e.g. Cu, Fe, Ni, and Zn) in combination with oxidizing nitrate, chlorate and perchlorate anions. The synthesized ECCs were analyzed by low-temperature single-crystal X-ray diffraction experiments, elemental analysis and IR spectroscopy. The thermal behavior of all compounds was investigated by differential thermal analysis and the sensitivities towards impact and friction was measured. Due to the lack of information about the properties of N -nitromethyl azoles, the complete insensitivity towards external stimuli of 2a and 2b supports first hints of a sensitivity decreasing influence of the N -nitromethyl moiety, which is highly desired when designing new high explosives. Additionally, the functional group is able to introduce meltability into molecular scaffolds.

Sukhanov G.T., Bosov K.K., Filippova Y.V., Sukhanova A.G., Krupnova I.A., Pivovarova E.V.

An N-glycidyl-5-aminotetrazole homopolymer was synthesized herein by nucleophilic substitution of 5-aminotetrazole heterocycles for chlorine atoms in poly-(epichlorohydrin)-butanediol. Copolymers of N-glycidyl-5-aminotetrazole and glycidyl azide with a varied ratio of energetic elements were synthesized by simultaneously reacting the 5-aminotetrazole sodium salt and the azide ion with the starting polymeric matrix. The 5-aminotetrazole-based homopolymer was nitrated to furnish a polymer whose macromolecule is enriched additionally with energy-rich terminal ONO2 groups and nitrate anions. The structures of the synthesized polymers were characterized by 1H and 13C NMR and IR spectroscopies, elemental analysis and gel-permeation chromatography. The densities were experimentally measured, and thermal stability data were acquired by differential scanning calorimetry. The insertion of aminotetrazole heterocycles into the polymeric chain and their modification via nitration provides an acceptable thermal stability and a considerable enhancement in density and nitrogen content compared to azide homopolymer GAP. By the 1.3-dipolar cycloaddition reaction, we demonstrated the conceptual possibility of preparing spatially branched, energy-rich polymeric binders bearing 5-aminotetrazole and 1,2,3-triazole heterocycles starting from the plasticized azide copolymers. The presence of the aforesaid advantages makes the reported polymers attractive candidates for use as a scaffold of energetic binders.

Chavez D.E., Tappan B.C., Kuehl V.A., Schmalzer A.M., Leonard P.W., Wu R., Imler G.H., Parrish D.A.

We report a [3+2] cycloaddition using 3,6-bis-propargyloxy-1,2,4,5-tetrazine and azides to synthesize energetic polymers containing 1,2,4,5-tetrazine within the scaffold. This work also includes [3+2] cycloaddition to crosslink azide containing glycidyl azide polymer (GAP). These reactions provide pathways for incorporation of 1,2,4,5-tetrazine into novel energetic materials using click-chemistry and provide an alternative polymer curing approach.

Larin A.A., Pivkina A.N., Ananyev I.V., Khakimov D.V., Fershtat L.L.

Nitrogen-rich energetic materials comprised of a combination of several heterocyclic subunits retain their leading position in the field of materials science. In this regard, a preparation of novel high-energy materials with balanced set of physicochemical properties is highly desired. Herein, we report the synthesis of a new series of energetic salts incorporating a (1,2,4-triazolyl) furoxan core and complete evaluation of their energetic properties. All target energetic materials were well characterized with IR and multinuclear NMR spectroscopy and elemental analysis, while compound 6 was further characterized by single-crystal X-ray diffraction study. Prepared nitrogen-rich salts have high thermal stability (up to 232°C), good experimental densities (up to 1.80 g cm−3) and high positive enthalpies of formation (344–1,095 kJ mol−1). As a result, synthesized energetic salts have good detonation performance (D = 7.0–8.4 km s−1; p = 22–32 GPa), while their sensitivities to impact and friction are quite low.

Bystrov D.M., Pivkina A.N., Fershtat L.L.

Energetic materials constitute one of the most important subtypes of functional materials used for various applications. A promising approach for the construction of novel thermally stable high-energy materials is based on an assembly of polynitrogen biheterocyclic scaffolds. Herein, we report on the design and synthesis of a new series of high-nitrogen energetic salts comprising the C-C linked 6-aminotetrazinedioxide and hydroxytetrazole frameworks. Synthesized materials were thoroughly characterized by IR and multinuclear NMR spectroscopy, elemental analysis, single-crystal X-ray diffraction and differential scanning calorimetry. As a result of a vast amount of the formed intra- and intermolecular hydrogen bonds, prepared ammonium and amino-1,2,4-triazolium salts are thermally stable and have good densities of 1.75–1.78 g·cm−3. All synthesized compounds show high detonation performance, reaching that of benchmark RDX. At the same time, as compared to RDX, investigated salts are less friction sensitive due to the formed net of hydrogen bonds. Overall, reported functional materials represent a novel perspective subclass of secondary explosives and unveil further opportunities for an assembly of biheterocyclic next-generation energetic materials.

Kofen M., Harter A.G., Klapötke T.M., Stierstorfer J.

During the last decade, energetic coordination compounds gained considerable attention due to the simple adjustments in their physicochemical properties. By combining different metal cations, energetic anions, and ligands, those compounds can be adapted for their intended use. This study used 1,5-dimethyltetrazole ( 3 ) as a highly endothermic, easily accessible, and insensitive ligand. It is a structural isomer to 1-ethyl-5 H -tetrazole (1-ETZ), which was recently described as a suitable ligand. 1,5-Dimethyltetrazole was synthesized using two different methods: (1) reaction of acetone with azido (trimethyl) silane and (2) reaction of acetoxime benzenesulfonate with sodium azide. Subsequently, 1,5-dimethyltetrazole was reacted with the perchlorate salts of different 3 d metals (e.g., Mn, Fe, Co, Ni, Cu, Zn) to obtain new energetic coordination compounds (ECCs). In addition, copper (II) complexes with 2,4,6-trinitro-phenolate anions were synthesized. The resultant complexes were investigated through low-temperature, single crystal diffraction experiments complemented by elemental analysis, infrared spectroscopy, and differential thermal analysis. Moreover, sensitivities towards impact and friction were investigated. In this study, all ECCs exhibited impact sensitivities between 2 and 10 ​J, friction sensitivities between 128 and 360 ​N, and thermal stabilities of up to 360 ​°C. 1,5-dimethyltetrazole (1,5-DMT) was synthesized using an easy, three-step synthesis procedure from cheap and commonly available starting materials, such as acetone, hydroxylamine, and sodium azide. Owing to its complete insensitivity and high thermal stability, 1,5-DMT serves as an ideal ligand for energetic coordination compounds (ECCs) when combined with 3d metals like copper (II) or zinc (II) perchlorate. Most ECCs exhibit excellent thermal stability together with safe handling. Despite no properties as primary explosives, they can be considered possible burning rate modifiers.

Benz M., Klapötke T.M., Stierstorfer J.

The highly energetic 1-nitrimino-5-aminotetrazole moiety can be obtained by direct nitration of 1,5-diaminotetrazole. The hydroxylammonium, 3,6,7-triamino-[1,2,4]triazolo[4,3- b ][1,2,4]triazolium (HTATOT) and potassium derivatives were synthesized in this study through acid-base reaction because of the expected promising properties. Especially the potassium derivative shows interesting characteristics for a use as primary explosive. All new compounds were characterized through multinuclear NMR and IR spectroscopy. The purities were checked via CHNO elemental analysis and the compounds’ sensitivities (IS, FS, ESD) were measured using the BAM 1 of 6 method. Based on the crystallographic densities (low-temperature X-ray diffraction experiments) and the calculated heats of formation (atomization method based on CBS-4M level of theory), the performance data were calculated using the EXPLO5 code. The potassium derivative thereby shows interesting properties for possible use as metal-free primary explosive (positive PETN initiation, T d ​= ​180 ​°C). The hydroxylammonium derivative shows astonishing detonation properties ( v D ​= ​9697 ​m·s −1 , p ​= ​38.1 ​GPa).

Dou H., Chen P., Hu L., He C., Pang S.

Oxygen-containing fused ring skeleton was constructed by one-step reaction with simple and effective method, and neutral energetic compounds with high performance were obtained by simple oxidation reaction. • Oxygen-containing fused ring skeleton was constructed by one-step reaction. • Energetic molecule 1 features with a nearly coplanar backbone. • Neutral compound 2 features outstanding detonation velocity, which is superior to the commonly used military explosive RDX. • This work provides a reference for designing a new energetic skeleton of oxygen-containing fused rings. Three neutral energetic compounds with a novel oxygen-containing fused ring were synthesized by starting from 4-amino-1,2,5-oxadiazole carbohydroximoyl chloride and 5-bromo-3-nitro-1- H -1,2,4-triazole, their structures fully characterized using multinuclear nuclear magnetic resonance (NMR) spectroscopy, infrared (IR), elemental analysis, and single crystal X-ray structuring. Their decomposition temperature, density and impact sensitivity were measured, their detonation performances were calculated by EXPLO5 v6.05.

Larin A.A., Ananyev I.V., Dubasova E.V., Teslenko F.E., Monogarov K.A., Khakimov D.V., He C., Pang S., Gazieva G.A., Fershtat L.L.

Two novel representatives of energetic (1,2,4-triazolyl)furoxans were prepared from the readily available (furoxanyl)amidrazones. Synthesized compounds were thoroughly characterized with IR and multinuclear NMR spectroscopy, elemental analysis and X-ray diffraction data. Analysis of structural features supported by quantum-chemical calculations revealed the main reasons for experimentally observed difference in thermal stability and mechanical sensitivity of both compounds. It was found that 3-cyano-4-(1 H -1,2,4-triazol-3-yl)furoxan is more thermally stable ( T d : 229 ​°C) than 4-azido-3-(1 H -1,2,4-triazol-3-yl)furoxan ( T d : 154 ​°C) and the latter compound is also more sensitive to impact and friction. In addition, both heterocyclic assemblies have high detonation parameters ( v D : 7.0–8.0 ​km·s −1 ; p : 22–29 ​GPa) exceeding those of benchmark explosives trinitrotoluene and hexanitrostilbene which enable their usability for various energetic applications.

Zhilin E.S., Ananyev I.V., Pivkina A.N., Fershtat L.L.

Nitrogen-oxygen organic materials constitute an important family of multipurpose high-energy materials. However, the preparation of energetic boosters and oxidizers for various civil and space technologies remains a challenging task and such materials usually require special precautions and fine tunability of their functional properties. To find a balance between energy and safety while retaining the oxidizing ability of target energetic materials, novel hybrid organic compounds comprising furoxan and 3,3-dinitroazetidine scaffolds enriched with additional nitro groups were synthesized. The prepared 3-(3,3-dinitroazetidinoyl)-4-nitrofuroxan and 3,3-dinitro-1-(2,2,2-trinitroethyl)azetidine have high nitrogen-oxygen contents (75-79%), positive oxygen balance to CO (up to +10.3%) and good experimental densities (1.75-1.80 g cm-3). A combination of superior detonation performance (D = 8.3-8.5 km s-1 and P = 32-33 GPa) and moderate mechanical sensitivity enables the application potential of these energetic materials as booster explosives or oxidizers. Additionally, their functional properties remain essentially competitive with other oxygen-rich energetic materials (pentaerythritol tetranitrate, ammonium dinitramide, and tetranitratoethane). Hirshfeld surface calculations supported by energy framework plots were also performed to better understand the relationship between the molecular structure and stability/sensitivity. This work unveils novel directions in the construction of balanced energetic boosters and oxidizers for various applications.

Bauer J., Benz M., Klapötke T.M., Stierstorfer J.

1,5-Diaminotetrazole is one of the most prominent high-nitrogen tetrazole compounds described in the literature. Interestingly the isomer 2,5-diaminotetrazole is nearly undescribed due to its challenging synthetic routes. 2,5-Diaminotetrazol (1) was successfully synthesized via amination of 5-aminotetrazole followed by various purification steps to separate it from isomeric 1,5-diaminotetrazole. In addition to the extensive characterization of 2,5-DAT further derivates by protonation, methylation and amination of the tetrazole ring were synthesized and characterized. The resulting tri-functionalized, ionic tetrazolium derivatives were combined with energetic anions (nitrate, perchlorate, azide, 5,5'-bistetrazole-1,1'-diolate (BTO2-)) to adjust and tune the properties of each compound. All compounds were intensively characterized including IR and multinuclear NMR spectroscopy, thermal analysis through DTA, X-ray diffraction and sensitivity testing. The purity was verified by CHNO elemental analysis and the energetic properties were calculated using the EXPLO5 code and the calculated enthalpy of formation (CBS-4M).

Bieniek J.C., Grünewald M., Winter J., Schollmeyer D., Waldvogel S.R.

A novel sustainable electrochemical synthetic route to N,N′-disubstituted indazolin-3-ones by direct anodic oxidation with mild reaction conditions, a simple galvanostatic setup, broad scope and excellent scalability is established.

Zhou J., Zhang J., Wang B., Qiu L., Xu R., Sheremetev A.B.

Energetic material is a very essential company of compounds, widely used in various fields, primarily in the military industry and space technologies. These compounds are unique in that they are capable of instantly decomposing to release enormous energy. The chemical diversity of energetic organic compounds is constantly increasing through the combination of various high-nitrogen frameworks and explosophoric groups, which follows the overall trend of increasing interest in their chemistry and applications. The scientific community is constantly looking for more powerful and less sensitive to external impulses energetic compounds for both military and civilian use. Herein, a detailed overview regarding classic and novel explosophoric groups and various frameworks, as well as a description of the selected synthesis for the target compounds, has been given for the time period since 2010. The physical properties and performances of benchmark and prospective compounds are also collected.

Kofen M., Lommel M., Wurzenberger M.H., Klapötke T.M., Stierstorfer J.

Shortening the alkyl chain in 1-(Azidoethyl)-5H-tetrazole (AET) to a methylene bridge results in the formation of highly sensitive 1-(azidomethyl)-5H-tetrazole (AzMT), which exhibits a greatly increased enthalpy of formation, hence a drastically increased detonation performance is calculated. Like AET, AzMT can be applied as ligand in the energetic coordination compounds (ECC) of several transition metals, showing the characteristics of primary explosives capable of initiating pentaerythritol tetranitrate. The ligand as well as all ECCs are fully characterized.